I have a simple setup now with a RB153 board as a simple NAT router with 4 bridged ports for lan and 1 port for WAN. I want to limit port 5 to 768k/128k for WAN traffic but still allow its local LAN traffic unlimited. So far the best i can do is set the 768k/128k for port 5 and that works but my local traffic is still shapped too which i don't want it to do.

make your queue matching rule with dst-address=!10.0.0.0/8 (if you use private ips from this subnet) and not dst-address=0.0.0.0/0

Cheers
Michal

if bridge - enable IP firewall for bridge

if more than one local subnet - create an address-list of all addresees

in mangle:
1) accept all traffic from local addressees (list) and to local addressees(list)
2) mark-connections to all traffic
3) mark-packet for all traffic

In queue tree on local and public interface create queues for packet marks.